This invention relates generally to a color cathode ray tube (CRT) screen exposure apparatus. More particularly, this invention is directed to an improved apparatus for effectively obtaining high and uniform luminance having desired light source pattern. A color CRT screen exposure apparatus is generally constructed in a housing 1 as briefly shown in FIG. 1. The housing 1 is provided with a lamp assembly 2 on its bottom side and a top 1a at its upper end for placing a faceplate P for a color CRT. Between the lamp assembly 2 and the faceplate p, a correction lens 3 for correcting the path of light irradiated by the lamp assembly 2 and a filter 4 for controlling the luminance of light are installed. A shutter 5 containing a slit 5a which partially passes light from the source is located between the correction lens 3 and the lamp assembly 2. In the FIG. 2, the lamp assembly 2 is shown as being constructed with a cooling chamber 21 having a round cavity 22 at its center and a high luminance mercury lamp 23 passing through the cooling chamber 21 and traversing the round cavity 22 to expose its body and a pair of regulators 24 located on both sides of the round cavity 22 regulating the exposing width of the lamp 23.
Since the high luminance mercury lamp 23 in the conventional color CRT exposure apparatus constructed as above is installed parallel to the longitudinal side of the faceplate exposing its body of a certain width as determined by the regulator 24 in the cooling chamber 21 having a round cavity 22 at the center thereof, the faceplate P can not be sufficiently irradiated by the source. Thus, exposure has to be made for a relatively longer period to have enough light land on the faceplate P. In addition, since the light source is of the cylindric shape, the luminance on every part of the faceplate P even at the same distance from the light source appears minutely irregular subject to angles formed between each part of the light source and the faceplate P, so that the quality of phosphor screen is degraded. The screen is further deteriorated by the presence of striped figure caused by light diffraction and interference at the regulator 24.
It is the object of the present invention to provide an improved color CRT exposure apparatus for concentrating light more efficiently in order to make the most of light for exposure and, more specifically, for establishing more desirable pattern of light source.